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QATENTED." FEBZ Vi868 Fig. 5.

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S. E. GHUB-BUCK AND ISAAC Y. CHUBBUCK, OF ROXBURY, MASSAGH- SETTS,ASSIGNCMSl TO THEMSELVES AND S. E. CHU'BBUGIQ' JR.

Letters APatent No. 74,750, dated February 25, 1868.

IMPROVEMENT IN PISTONS.

TO ALL WHOM IT MAY CONGERN:

Be it known that we, S. E. CHUBBUGK and ISA'C Y. GrIUBBUCK, bothofRoxbury, in the county of Nolfolk, and State of Massachusetta'haveinvented certain new and useful Improvements in Pistons forSteam-Engines; and we do hereby declare that the followingis a full andexact description thereof, reference being had to -the accompanyingdrawings, and tothe letters of reference marked thereon, thse drawingsmaking part of this. specification. With reference to theml A Figure 1is a perspective View of a. piston exhibited in position within thesection of a steam-cylindertthe follower'ha'ving been removed'. from thepiston to show the interior construction and arrangement.

Figure 2 is aperspective viewof two of the packing-ring secti'ons'formedin one piece. i

Figure 3 shows the same formed in two separate parts.

Figure 4 shows the sametwoparts of a packing-ring section adjustedtogether in their proper but separate relation. l i Figure 5 is aperspective view of the pistons follower. A

The nature of our improvement relates to the construction of thering-sections and the devices for applying and' adjusting them, andrendering them self-adjusting, substantially` as I will proceed todescribe.

A is a. section of a steam-cylinder, and within it isshown the piston,having the usual baeksface plate and centre hub, b, to receive thepiston-rod and upon these are cast, in the usual manner, the arms c andhubs CZ, to which the follower e may be secured by screw-bolts, the backplate and the follower embracing, in the usual manner, thepacking-rings. Inadditien to these, in our improvement we cast a.guiding-socket or box, f, open on the side next t'o the follower', anda-t theouter'end, and radiating from the centre hub between the arms c.The back side of this socket extends radially to the rim g of thepiston. This rim extends around *the piston, and formsa surface toembrace the packing-rings upon the side opposite the follower, and maybefdirectly on the back plate ofthe piston, or may be elevated somewhatfrom it, with space between, as shown, for lightness. The packing-ringsare made up of the ring sections H.- The peculiarity of these sectionsis found in the different 1 and particular form of the two 'endsofeaeli'section, (see i j,) and their arrangement, togetherwith thespringwedge K, (see Iig. 1.) The form of this wedge K, with enlargedhead, allowing it to recede only to a given point, and the applicationof a spring, Z, to keep it pressed-out radially against tliepeculiarly-formed ends ofthe ringsections, will be readily understoodfrom the drawing. v

That the form ofthe different ends of sections H may bebetterunderstood, together with their utility, -we

Will explain that the ends jare formed in a single angular line-orplane, (see igs. 1, 3, 4,) while the other end, e', is formed incoincidence with two intersecting angular lines or planes, n m, theangles 22 and g each being formed to correspond with the angles oftheheads of wedges K, and the angle 'r to match the extended angular end, qj, of theadjacent section when arranged together. The utility of thisconstruction of the ends of the ring-sections consists in. not allowingthe wedge to pass through against the cylinderas the parts wear away,and in affording therewith the facility at the same time to break thedirect communication ofthe steam through the joint when the sections arearranged in reverse order in the different circular series, as shown ings. 4 and 2. These sect-ions are also furnished with the lugs u, which,while they generally keep the rings from turning around, are so formedand tted,with reference to the ends of arms c, that in a horizontalcylinder' they support the two ring-sections, which come in a verticalposition, from slidingdown upon the wedges, so as to relieve thecontiguous section from its action. Fig. 2 shows two sections in reverseorder, and formed into one, yet embodying the same peculiarities, andacting, perhaps, in some cases quite as efficiently.

It will be observed that this construction affords perfect facility forexamining the adjustment of the parts while in position for working. Byremoving the follower e the interior parts are exposed to View, withoutany' disarrangement or disturbance of any of them.

Having described our improvements, what we claim as our invention, anddesire tosecure by Letters Patent, is as follows:

1. We claimthe peculiar construction ofthe ring-sections H,substantially as described and shown.

2. We claim the open-sided radial grooves ff,';in combination with thespring-wedge K, Substantially as described.

3. We claim the lugs u, in combina-tion with the arms o r approximatelyvertical position, substantially as described.

c, to support those sections which work in n. vertical S. E. CHUBBUCK,I. Y. CHUBBUCK.

Witnesses:

D. N. B. COFFIN, Jr., IRAII D. SPAULDING.

